What are the regional weather characteristics under the control of subtropical high? Why?

It is hot and dry in summer, mild and rainy in winter, with the temperature of 0℃~5℃ in winter and 25~30℃ in summer. The annual precipitation is about 350~900 mm, which is concentrated in summer. Winter precipitation only accounts for 20 ~ 40% of the annual precipitation, and the maximum monthly precipitation is more than 3 times of the minimum monthly precipitation.

Subtropical high plays an important role in the transport and balance of water vapor, heat and energy between middle and high latitudes, and is an important system of atmospheric circulation.

The vertical motion of the atmosphere between the east and the west is very different: in the east of high pressure, the sinking motion is particularly strong, and the descending airflow is heated by adiabatic compression, resulting in a strong subsidence inversion, which is called trade wind inversion. This strong inversion stratification is very stable, which inhibits the development of vertical convection, makes the weather continue to be fine, and forms a dry climate zone on the west coast of subtropical continent.

The western part of subtropical high is the convergence and rising area of low-level warm and humid air, which is prone to thunderstorm weather.

Extended data:

In summer, controlled by subtropical high, the airflow sinks and there is little rain. In winter, the subtropical high moves to the low latitude, and the westerlies in this climate area have frequent cyclone activities and abundant precipitation. At the same time, the climate is mild and humid because the west wind blows from the warmer ocean in winter (the difference in thermal properties between land and ocean).

A high-pressure system located in the subtropical zone (about 20 ~ 30 latitude). It is elliptical, and its long axis is roughly parallel to the latitude circle. It is a warm dynamic system, which is most obvious on the isobars of 700 hectopascals and 500 hectopascals and belongs to a planetary scale system (see weather system).

Subtropical high plays an important role in the transport and balance of water vapor, heat, energy and angular momentum between middle and high latitudes, and is an important system of atmospheric circulation. Subtropical high is mainly located in the ocean and exists all the year round. According to different geographical locations, they are called North Pacific High, North Atlantic High, South Pacific High, South Atlantic High and South Indian Ocean High respectively.

Because these high-pressure packages surround the whole subtropical region, they are collectively called subtropical high-pressure areas. Sometimes, the subtropical high can be divided into smaller high-pressure units, and some small units can also be located on the mainland. The monomer located in the South China Sea in winter is called the South China Sea High.

Characteristics: The main cause of the subtropical high pressure belt is dynamic action (see jet stream), and its high pressure ridge line (the line connecting the isobar or contour line with the maximum anticyclone curvature) is located in the downflow area of Hadley meridional circulation and Ferrer meridional circulation (see atmospheric circulation). How sunny the weather is.

According to legend, when the horse-carrying sailboat from the Atlantic Ocean to the West Indies entered the latitude where the subtropical high was located, it was calm for several weeks, and finally it had to be thrown into the sea because of the exhaustion of water and food. Therefore, horse latitude is often regarded as synonymous with subtropical high in Europe and America.

As far as the subtropical high is concerned, the vertical motion of the atmosphere between the east and the west is quite different: in the east of the high, the sinking motion is particularly strong, and the descending airflow is heated by adiabatic compression, resulting in a strong subsidence inversion, which is called trade wind inversion. This strong inversion stratification is very stable (see the static atmosphere, which inhibits the development of vertical convection, makes the weather continue to be fine, and forms a dry climate zone on the west coast of the subtropical continent (see the Mediterranean (type) climate).

In the west of high pressure, the downdraft and inversion layer are weak, which makes the warm and humid air converging and rising in the lower layer easily break through the inversion layer to form convection, so there are many thunderstorms.

In summer, the western Pacific high and the north Pacific high are generally divided into two large units: the large unit located in the western Pacific is called the western Pacific high and the large unit located in the eastern Pacific is called the eastern Pacific high. In the westerly belt on the north side of the ridge line of high pressure in the western Pacific, there are frequent cyclones and fronts, which often produce rainy or rainstorm weather.

The main rain belt in eastern China is often located at a distance of 5~8 latitudes north of the ridge line of high pressure. The seasonal variation of the ridge line of high pressure in the western Pacific corresponds to the seasonal displacement of the main rain belt in eastern China.

Baidu encyclopedia-subtropical high

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